High loft nonwoven fabric having randomly directed fibers therein andmethod of producing the same

ABSTRACT

A HIGH-LOFT, NONWOVEN FABRIC AND A METHOD FOR PRODUCING IT THAT COMPRISES ADVANCING A SURFACE HAVING AN OPEN PATTERN OF TACKY ADHESIVE, BONDING A PLURALITY OF FLEXIBLE ELEMENTS IN THE ADHESIVE RANDOMLY AT LEAST PARTIALLY IN THE MACHINE AND CROSS DIRECTIONS, PREPARING A WEB OF OTHER FLEXIBLE ELEMENTS EXTENDING SUBSTANTIALLY IN THE MACHINE DIRECTION, BONDING THE WEB IN THE ADHESIVE, AND AT LEAST PARTIALLY CONSOLIDATING THE ADHESIVE INTO A BACKING LAYER   WHILE LOOPING THE MACHINE DIRECTION ELEMENTS OUTWARDLY FROM THE ADHESIVE BACKING LAYER.

CL 9 1973 R. J. PEERENBOOM 3,764,426

HIGH-LOFT, NONWOVEN FABRIC HAVING RANDOMLY DIRECTED FIBERS THEREIN, AND METHOD OF PRODUCING THE SAME Filed Deo. 27, 1971 4 Sheets-Sheet 1 Oct. 9, 1973 RA J, PEERENBOOM 3,764,426

HIGH'LOFT, NONWOVEN FABRICv HAVING RANDOMLY DIRECTED FIBERS THEREIN, AND METHOD OF PRODUCNG THE SAME Filed Dec. 27 1971 4 Sheets-Sheet 2 i l!!! 2p. l l A ,f

+- 57. 4. -ffg. 4

0t- 9 1973 R. J. PEERENBOQM 3,764,425

HIGHLOFT, NONWOVEN FABRIC HAVING RANDMLY DIRECTED FIBERS THEREIN, AND METHOD OF PRODUCING THE SAME Filedl Dec. 27, 1971 4 Sheets-Sheet 3 -T-g.. Ms! @Wirf/av;

Oct. 9, 1973 R. J. PEERENBOOM 3,754,425

HIGH'LOFT, NONWOVEN`FABRIC HAVING RANDOMLY DIRECTED FBERS THEREIN, AND METHOD OF PRODUCING THE SAME Filed Dec; 27, 1971 4 Sheets-Sheet 4 `United States Patent O1 iice 3,764,426 Patented Oct. 9, 1973 HIGH-LOFT, NONWOVEN FABRIC HAVING RAN- DOMLY DIRECTED FIBERS THEREIN, AND

METHOD F PRODUCING THE SAME Robert J. Peerenboom, Little Chute, Wis., assignor to Kimberly-Clark Corporation, Neenah, Wis.

Filed Dec. 27, 1971, Ser. No. 212,167 Int. Cl. D04h 3/00, 11/00 U.S. Cl. 156-72 15 Claims ABSTRACT 0F THE DISCLOSURE Related applications George H. Saunders, Robert C. Sokolowski, and Robert I. Stumpf, No. 498,929, filed Oct. 20, 1965, and replaced by a continuation application of the same inventors, Ser. No. 79,287, filed Oct. 8, 1970.

Ronald H. Wideman, Ser. No. 551,605, filed May 20, 1966 and now U.S. Pat. No. 3,553,064, issued Jan. 5, 1971.

Robert I. Stumpf and William L. Mowers, Ser. No. 553,483, fied May 27, 1966 and now U.S. Pat. No. 3,553,065, issued Jan. 5, 1971.

Robert I. Stumpf, Ser. No. 31,225, filed Apr. 23, 1970, and now issued as Pat. No. 3,709,768.

Robert I. Stumpf, Ser. No. 820,224, filed Apr. 29, 1969, and now issued as Pat. No. 3,687,754.

Robert I. Stumpf and William I. Mattes, Ser. No. 23,929, filed Mar. 30, 1970, and now issued as Pat. No. 3,687,796.

Herman G. Minshell, Robert J. Stumpf and William .I Mattes, Ser. No. 77,840, filed Oct. 5, 1970.

Description of the invention The present invention relates in general to nonwoven fabrics and, more particularly, to a method forproducing a high-loft, nonwoven, fabric having improved crossdirectional strength as well as accented color characteristics, and the fabric produced by the method.

In recent years, many different types of nonwoven materials have been produced, both to replace conventional woven fabrics and, also, to create new markets in which woven fabrics have not yet become established. This is particularly true in the case of materials for singleuse and disposable products, such as: sanitary supplies, hospital garments, disposable sheets, and the like. For these applications the nonwoven fabric is generally made in continuous sheet form with one or more layers of staple length fibers and/or a reinforcing scrim structure adhesively bonded together or laminated between plies of other material such as cellulosic wadding and platsic sheeting. The lfibers may be natural, synthetic or `various blends and, of course, the particular composition of the nonwoven fabric is greatly influenced by its intended use.

Exemplary of such nonwoven fabrics are those disclosed in U.S. Pat. Nos. 2,902,395, 3,047,444, 3,072,511, 3,327,708, 3,484,330, 3,553,064, and 3,553,065 and the aforesaid copending United States patent application, Ser. No. 79,287, all of which are assigned to the same assignee as the present application. While the products disclosed in the foregoing issued patents and copending applications have many different attributes and characteristics, they all have one thing in common-viz., the principal fibers are nearly all disposed substantially parallel to the surfaces of the nonwoven material. As a result, the material is either relatively thin and fiat or, such substantial thickness and surface texture as are imparted to the fabric are provided by creping or embossing various layers of the material or, in some instances, the final nonwoven fabric.

It is also well-known that natural fibers, particularly cotton and wool, have an inherent kink or crimp resulting from the way in which these fibers grow. This natural crimp is, of course, highly beneficial and contributes largely to the strength of thread made of a multiplicity of staple length fibers. In addition, it is the natural crimp of these fibers that imparts certain characteristics of texture and body to materials woven therefrom.

In contrast, synthetic fibers, as initially formed, do not have any appreciable kink or crimp since they are generally formed in continuous monofilaments. However, it is also well-known that most synthetic fibers can be crimped and heat-set by passing the fibers through a heated stuffing box.

In the aforesaid copending application, Ser. No. 31,225, now Pat. No. 3,709,768 and in its parent application, Ser. No. 769,959, now abandoned, both of which are assigned to the assignee of the present invention, there is disclosed a method for forming high-loft, nonwoven materials with a pleasing surface texture and appearance. That method obviates the necessity for employing creping, embossing or other texturizing operations to increase the bulk or thickness of the material or to improve its surface texture. The fabric is made by first embedding a web of fibers in an open pattern of adhesive and, thereafter, at least partially consolidating the adhesive into a substantially continuous backing layer while looping the fibers outwardly from the backing.

Additionally, in the aforesaid copending application, Ser. No. 820,224, now Pat. No. 3,687,754, assigned to the assignee of the present invention, there is disclosed a method for forming a high-loft, nonwoven fabric having the pleasing structural and aesthetic properties thereinbefore described and which is further characterized by a high degree of stretchability and elasticity, particularly in the machine direction.

Although the fabrics produced by the methods disclosed in the last two above named applications have both desirable structural properties and pleasing aesthetic properties, a characteristic common to both of the fabrics is that the strength of the fabrics in the cross or transverse direction is less than desired in some instances. The cross-directional strength of such fabrics tends to preclude their use in certain products where they would otherwise find advantageous use. In this connection, however, it should be understood, that both of the above fabrics have many uses that do not require additional crossdirectional strength in excess of that normally exhibited by the fabrics.

Accordingly, it is a primary object of the present invention to provide an improved high-loft, nonwoven fabric of the foregoing type which is characterized by the inclusion of fibers extending, at least partially, in the cross direction of the fabric, which fibers may significantly improve the cross-directional strength in the event such fibers are generally uniformly distributed throughout the surface area of the fabric or which can provide localized cross-directional 'strength in finite areas where such fibers are applied.

Another primary object of the invention is the provision of a method for making a high-loft, nonwoven fabric having a splotchy, marbelized appearance, in the event the color of the fibers extending in the cross direction of the fabric is different from other fibers utilized in producing the fabric.

A further object of the invention is the provision of a method for making high-loft, nonwoven fabrics wherein the density of fibers being bonded in the adhesive in both the machine and cross directions may be varied to produce either localized clumps of fibers in the adhesive or generally uniformly applied fibers throughout the area of the fabric.

Yet another more specific object of the present invention is the provision of the above method whereby the plurality of flexible fibers or elements extending in both the machine and cross directions may be of a different color than the web of other fiexible fibers or elements that extend substantially in the machine direction and which, upon consolidation, produces a high-loft, nonwoven fabric having a marbelized, splotchy appearance in both the machine and cross directions.

Other objects and advantages of the present invention will become more readily apparent upon reading the following detailed description and upon reference to the attached drawings, in which:

FIG. 1 is a schematic View, in side elevation, of one form of apparatus embodying features ywhich may be employed to produce a high-loft, nonwoven fabric of the present invention;

FIG. 2 is a fragmentary plan view of an illustrative web of base material while still supported on a conveyor belt, somewhat simplified and exaggerated for the sake of clarity of illustration, with portions broken away to expose the various layers;

FIG. 3 is a fragmentary plan View of one embodiment of the product made by the apparatus of FIG. l;

FIGS. 4 and 5, respectively, are greatly enlarged, simplified, and somewhat exaggerated sectional views taken substantially along the lines 4 4 and 5 5 in FIG. 3;

FIG. 6 is an enlarged schematic detail View, in side elevation, of the forming drum and gathering blade of the apparatus shown in FIG. 1;

FIG. 7 is an enlarged schematic side elevational view illustrating, in somewhat idealized fashion, successive stages in the sequence of gathering and looping of individual fibers;

FIG. 8 is an enlarged schematic fragmentary view, taken substantially along the line 8 8 of FIG. 7, here showing a fragment of the fiber web and adhesive pattern with illustrative fibers attached to the adhesive;

FIG. 9 is a simplified schematic view, taken substantially along the line 9 9 of FIG. 7, here showing the fragment of the fiber web and adhesive pattern depicted in FIG. 8 at a later stage in the loop forming sequence;

FIG. l is an enlarged schematic bottom view showing the sequence of the partial consolidating or closing of the open pattern of adhesive to form a discontinuous adhesive backing;

FIGS. 11 through 14, illustrate in plan view, exemplary alternative adhesive patterns that may be used for the base web in practicing the method of the present invention;

lFIG. l is an enlarged side view of exemplary apparatus of the present invention for applying a plurality of fibers extending in both the machine and cross directions which is added to apparatus illustrated in FIG. l;

FIG. 16 is a view of a portion of the apparatus of FIG. 15, and taken substantially along the lines 16-16 therein; and

FIG. 17 is a fragmentary plan view similar to FIG. 2a, here particularly illustrating the application of fibers extending generally in the cross direction of the web in accordance with the method of the present invention.

While the invention is susceptible of various modifications and alternative forms, a specific embodiment thereof has been shown by way of example in the drawings and will herein be described in detail. It should be understood., however, that it is nQt intended t@ limit the. invention to the particular form disclosed, but, on the contrary, the intention is to cover all modi-fications, equivalents and alternatives falling witin the spirit and scope of the invention as expressed in the appended claims.

The environment of the invention To produce a high-loft, nonwoven fabric, a base web of fibers is prepared and an open adhesive pattern is applied to one side of the web. Different procedures have been used in preparing the base web. For example, textile length fibers may be processed through conventional cotton card machinery to produce a carded web for the base web. In such a carded web 50% to 70% of the fibers may be oriented substantially parallel with the machine direction. It has been found, however, that a more uniform product has been obtained with the method of the present invention by using base webs having a higher percentage of the fibers alined with the machine direction such, merely by way of example, as a highly drafted web in which, as a result of the drafting process, to of the fibers may be alined with the machine direction. Such webs of bonded, highly draft fibers, of course, have substantial utility in themselves and are the subject, for example, of the aforesaid copending application, Ser. No. 79,287 and U.S. Pat. No. 3,553,065.

One aspect of the present invention, however, :goes far beyond the preparation of an adhesively bonded carded web of the products and methods disclosed in those t-wo applications, and results in the formation of an improved material having a high-loft, nonwoven surface which is significantly different from the nonwoven web utilized as the base material.

Broadly stated, the method of the present invention involves utilizing a base web of the type hereinbefore described in conjunction with a plurality of fibers or elements that are generally randomly oriented in the machine and cross directions either uniformly throughout the surface of the base web or in smaller localized areas thereof and, thereafter, performing the subsequent steps of: l) reactivating the open pattern of adhesive in which the elements are embedded; and (2) consolidating or partially consolidating the adhesive into a backing layer, while (3) simultaneously looping the portions of the elements of fibers spanning the open spaces of the adhesive outwardly from the backing layer formed by the consolidated or partially consolidated adhesive. The resulting product is characterized by the high-loft or deep pile of the loops of fibers which extend outwardly from the adhesive backing and by its improved cross-directional strength in those areas where the randomly oriented fibers extend in both the machine and cross directions. Additionally, where the randomly app-lied fibers extending in both the machine and cross directions are a different color than the fibers comprising the base web, the resulting product may have a splotchy, marbelized appearance in addition to providing improved cross-directional strength. Moreover, the method contemplates other control parameters in the application of the random fibers that are applied in both the machine and cross directions to vary the appearance and strength-improving capabilities provided by the method.

The particular depth of pile or degree of loft of the loops, of course, depends upon a combination of control parameters, including, for example: the type of denier of the base fibers; and the amount of and spacing within the original adhesive pattern; the angle of the gathering blade; and the relative speeds of fabric delivery to and fabric discharge from the gathering blade; as will be discussed hereinafter.

By way of background, the basic method for producing a high-loft nonwoven fabric will now be described in detail. Turning now to the drawings, FIG. 1 schematically illustrates an exemplary apparatus for producing a high-loft nonwoven fabric. This apparatus includes a web forming section 10 and au adhesive compacting and fiber looping section 30. The web forming section is generally similar to the apparatus disclosed in the aforesaid copending application, Ser. No. 79,287, with certain modifications as disclosed in the U.S. Pat. No. 3,553,065, but it is here shown in more complete and visible form than shown in either of those disclosures. It will be appreciated as the ensuing description proceeds, that fiber webs made in accordance with the method disclosed in the aforesaid copending application, Ser. No. 79,287, are also usable with the subsequent method steps for producing the hereinafter described fabric, as are carded webs and webs prepared by other processes.

As shown in FIG. 1, multiple slivers 11 of textile fibers are drawn from their respective supply cans (not shown) into a draw frame 12 which comprises a series of pairs of grooved rolls 13; the rolls of each pair being driven by appropriate gearing (not shown, but well known in the art) at a peripheral rate of speed somewhat faster than the rate of operation of the preceding pair. Merely by way of example, the pairs of rolls 13 may be adjusted to provide an overall increase of speed and, therefore, an extent of fiber draw on the order of :1 through the draw frame 12. As the juxtaposed sliver pass through draw frame 12, the individual fibers are drafted and spread out to form a flat, striated web of substantially alined fibers as shown at 14. Web 14 is maintained adjacent a supporting conveyor sheet 15 on the surface of which adhesive has been previously applied in a preselected pattern.

In this embodiment, the conveyor sheet 15 comprises an endless conveyor belt treated on at least its upper surface with a release agent. One example of such a belt comprises woven glass fiber with a surface coating of tetrafiuoroethylene resin. Other examples of release coatings are well known, and comprise such materials as silicones, fatty acid metal complexes, certain acrylic polymers, and the like. Heat resistant films or thin metal sheets treated with release agents may also be used as the carrier sheet.

lPrior to the time the web 14 is packed up by the belt 15, the latter has imprinted on its release-treated surface a pattern of flexible, thermoplastic adhesive such as is shown at 16 in FIG. 2. It will be understood that, as shown in FIG. 1, the adhesive is actually on the underside of belt 15 which becomes the upper surface after passing around roll 17, at which time the adhesive pattern 16 directly contacts the fiber web 14. The pattern is shown as being visible in FIG. 2 only for illustrative purposes.

The belt 15 is fed around roll 17 at a speed slightly in excess of the delivery speed of the final pair of rolls 13 of draw frame 12 in order to maintain web 14 under slight tension, whereby the individual highly-drafted fibers are retained in their alined and tensioned condition. Drive rolls 18, 19 are rotated (by suitable drive means, not shown) to drive belt 15 at a speed sufiicient to maintain the proper tension on the web 14.

In the method shown for applying adhesive, the belt 15 is fed through a nip formed between a printing roll 20 and a back-up roll 21 maintained in very light pressure engagement therewith. The surface of printing roll 20 is provided with an intaglio pattern to which adhesive may be supplied in various ways well known to those skilled in the art. For example, in the aforesaid application, Ser. No. 31,225, now Pat. No. 3,709,768, a system is schematically disclosed wherein the lower portion of the printing roll 20 picks up adhesive directly from a dip pan, with excess adhesive being removed by a doctor blade, thus having only the intaglio patterned surface filled. However, it has been found that more satisfactory results are obtained by pumping or otherwise transferring adhesive 22 from a supply pan 23 to a reservoir located immediately above an inclined doctor blade 24-the reservoir being defined in part by the upper surface of the inclined doctor blade and the adjacent portion of the rotating peripheral surface of the printing roll 20. Thus, as the printing roll 20 rotates (in a counterclockwise direction as viewed in FIG. 1), the intaglio patterned surface thereof is filled with adhesive 22, excess adhesive is removed by the doctor blade 24. and a metered amount of adhesive is then transferred to the undeside of release coated belt 15 in a preselected pattern. The pattern shown in FIG. 2 is in the form of an open diamond pattern of adhesive.

The particular dimensions of the intaglio pattern employed and, indeed, the actual pattern itself, are not critical to the practice of the invention in its broadest aspects. Thus, it has been Ifound that patterns other than the illustrative diamond pattern hereinabove referred to can be utilized, and certain of such patterns will be subsequently described in connection With FIGS. l1-14. For illustrative purposes, however, it is noted that excellent results have been achieved where a diamond pattern was employed in which adjacent lines of adhesive were spaced apart in both directions by 1A, and wherein the intaglio printing roll 20 had adhesive cells or lines 0.007 deep and 0.025 wide. In certain instances, however, it has been found that the dimensions of the adhesive cells or lines, together with their spacing, are critical and must differ from the foregoing exemplary dimensions, and certain of such other arrangements are disclosed in the aforesaid copending application, Ser. No. 77,840 and which is assigned to the assignee of the present invention.

Since the surface of belt 15 is treated with a release coating, the adhesive remains substantially on the surface with no penetration therein and is preferably in a somewhat tacky condition. The printed belt is drawn from the printing nip around roll 17 positioned closely adjacent the output end of draw frame 12 and, as stated above, at a speed slightly in excess of the delivery speed of the last two rolls in the draw frame. The web 14 emerging from the draw frame 12 is deposited on the tacky adhesive 16 on belt 15 and held in tensioned engagement therewith by the adhesive and the above-mentioned speed differential. This continuous tension prevents the fibers in the web from losing their highly-drafted and alined condition.

In practicing the method additional alined and highlydrafted fibers may be added to the web 14 on the adhesively printed belt 15. For this purpose, a second draw frame 25 similar to the draw frame 12 is provided to draw additional slivers 26 of fibers from their supply cans (not shown) and, after drafting and alining them, to deposit the fibers on the moving web 14 carried by the belt 15. In such cases, the amount of adhesive printed on the belt 15 may be increased to insure that some of the adhesive in the adhesive pattern 16 penetrates the fibers of the web 14 drawn from the draw frame 12 and reaches the fibers drawn from slivers 26 which pass through the second draw frame 25. The arrangement is such that the adhesive contact between the fibers drawn from slivers 26 and the pattern 16, together with the speed differential of the belt 15 relative to the last pair of rolls in the draw frame 25, maintains the fibers drawn from slivers 26 under slight tension, whereby they also maintain their highly-drafted and alined condition.

The fibers deposited on the web 14 from draw frames 12 and 25 need not be the same kind, size, color or quantity. Nor, for that matter, do the fibers of the slivers 11 and 26 need to be uniform in these respects as they are drawn into the draw frames 12 and 25. Thus, various blends of liber sizes, kinds, colors and quantities can be deposited across the web 14 from each of the draw frames 12 and 25 and in various combinations of first and second layers of fibers. Additional draw frames can also be empolyed if desired. The fibers from each of the draw frames 12 and 25 pass under respective bars 27 and 28 before being deposited on the belt 15.

An example of the web 14 formed on the illustrative apparatus 10 (FIG. l) is shown in FIG. 2. As previously mentioned, a series of parallel and diagonally disposed lines of adhesive are printed in criss-cross fashion on the belt 15 to form the pattern 16 of adhesive having substantially open spaces in the configuration of diamonds. The fibers making up the components 14a and 14b of the web 14 are substantially all alined in the direction of web movement.

Following deposit of web components 14a and 14b on the adhesive printed belt 15, the belt is drawn around a heated curing drum 29 Where fusing and curing of the adhesive is substantially completed while the web 14 is maintained in firm contact therewith to bond the individual fibers. To insure effective heating and fusing of the adhesive, it is desirable that travel of the combined belt and web be around a substantial portion of the drum 29. In the illustrated embodiment, a y roll 29a is positioned to apply tension on the combined belt and web as they travel around the drum 29 to insure complete embedment of the fibers in the adhesive. |I'he fibers of the web 14 are thus bonded together while retaining their highlydrafted and substantially alined condition in the particular pattern in which they were deposited on the open pattern of adhesive 16 printed on the belt 15.

After leaving the fly roll 29a, the combined web 14 and belt 1S are preferably passed over the drive roll 19, which also serves as a cooling drum to set the adhesive. The bonded web 14 is stripped from the release-coated surface of the belt by the guide roll 31 as the web leaves the cooling drum 19.

While various well-known adhesives may be employed in the foregoing process, advantages reside in the use of plastisols, which are colloidal dispersions of synthetic resins in a suitable organic ester plasticizer, and which, under the influence of heat, provide good binding power while remaining soft and flexible. While many adhesives of this type are known, those found particularly useful for incorporation in the product of this invention include vinyl chloride polymers, and copolymers of vinyl chloride with other vinyl resins, plasticized by organic phthalates, sebacates, or adipates. These provide a fast curing plastisol adhesive characterized by relatively low viscosity, low migration tendencies, and minimum volatility. Such -adhesive remains soft and flexible after curing, and can be reactivated by subsequent heating.

It has been found that other adhesives may be employed in the process-for example, organisols utilizing resins such as the vinyl chloride polymers and copolymers. Furthermore, still other adhesives may be employed provided that they satisfy specified characteristics in the base web produced in the web forming section 10, and in the finished fabric produced in the adhesive compacting and fiber looping section 30 (FIG. 1), In general, such adhesives should be applied to the base web by procedures which will not disarrange the fibrous structure of theweb; such adhesives should heat-set at temperatures below the degradation temperature of the fibers in the base web 14 to secure bonding of the fibers to the adhesive; such adhesives should be reactivatable in the subsequent adhesive gathering and consolidation stage of the process; and such adhesives should form a flexible backing layer for the finished fabric and should strongly bond the fiber loops in place. For example, emulsions of thermoplastic resins such as acrylics and rubber-like compounds, illustratively ABS, have the requisite properties to serve as the bonding adhesive for the web 14.

The base material, made as heretofore described and comprising a web 14 of highly-drafted fibers embedded in an open adhesive pattern, is fed into the adhesive consolidating and fiber looping section 30 of the apparatus shown in FIG. 1. As shown here, the web 14 continues directly from the web forming section 10 to the consolidating and looping section 30. It should be appreciated, however, that the web discharged from section 10 could be rolled up for storage or transport and then subsequently unrolled and fed into section 30. Also, as previously mentioned, other webs such, merely by way of example, as those made in accordance with the methods q islsed in the aforesaid @pending application, Ser- 8 No. 79,287 and U.S. Pat. No. 3,553,065, can be further processed in section 30.

As illustrated in FIG. 1, the web 14, while still under tension, is fed around an idler roll 32 and on to the surface of a heated forming drum 37. In its preferred embodiment, the drum 37 is made of metal with =a highly polished, chromium plated surface which is heated and maintained at a temperature of approximately 250 F. Also, the web 14 is arranged to travel a substantial distance around the drum 37 with the open pattern of adhesive 16 in contact with the heated drum surface. As the web 14 is fed onto the drum 37, the heat from the drum surface reactivates and softens the adhesive printed on the underside of the web, causing it to be tacky and to adhere slightly to the drum surface, thereby maintaining the web under constant tension. The drum temperature, which is maintained at about 250 F., is, however, maintained below the melting point of the adhesive to prevent dispersion of the adhesive into the fibers of the web.

The web 14 of fibers and softened adhesive is reformed by the cooperative action of the drum 37 and a gathering blade 38 having a flat edge 39. The blade edge 39 operates to consolidate the open adhesive pattern 16 into a substantially continuous backing layer of adhesive, while simultaneously looping the fibers of the web outwardly from between the open spaces in the original adhesive pattern. The reformed and consolidated material 40 then leaves the blade edge 39 and moves onto a fiat take-off surface 41 and `a discharge conveyor 52.

Turning now to FIGS. 7-9, the method of making the high-loft, nonwoven fabric 40 will be explained in greater detail in connection with an illustrative sequence of the gathering and looping of a single fiber of the web 14 and the consolidation of its two original points of adhesive attachment in the pattern 16. As seen in FIG. K8, the fiber has a portion P which extends across the open space of the diamond pattern of adhesive 16 from point A to point B where it is embedded in the adhesive. Referring to FIG. 7, the series of views in this figure illustrates how the portion P of the fiber is formed into a loop; viz, when point A being carried around the heated drum 37 irnpinges against the gathering blade edge 39, its forward motion is halted and it is scraped along the surface of the drum, while point B continues to advance with the drum surface since, due to its softened and tacky condition, it adheres to the smooth drum surface. As point B advances relative to point A, the portion P of the ber between points A and B is caused to bow outwardly from the drum surface. Finally, point B overtakes point A and these points of adhesive are substantially consolidated as seen in FIG. 9. In the meantime, fiber portion P has been looped outwardly from the drum surface.

It will, of course, be understood that while looping of fiber portion P is occurring, additional adhesive points C- D, etc., travelling around the drum 37 impinges against the gathering blade edge 39 causing a consolidation of these adhesive points and looping of their intermediate Ifiber portions P1 as is also indicated in FIG. 9. 'Ihis occurs simultaneously at all points across the web at the blade edge, producing a substantially continuous backing layer of adhesive from which extends the multiplicity of loops fored by the fibers of the base web. The thus formed substantially consolidated layer of adhesive is carried away from the blade edge 39 along the take-off surface 41 and provides a substantially continuous backing layer for the outwardly looped fibers, thus producing the fabric 40.

Another important feature is that not only does each fiber portion P loop outwardly from the drum surface b ut, also, as the loop is formed it turns, reaching a position in the fabric 40 generally perpendicular to the direction of the original alinement of fiber portion P. Thus, the fiber loops arrange themselves so that the plane of each loop is substantially normal to the original fiber alinement shown in FIG. 8. The reason for the loop twisting as it is formed may be explained by this observation. If two spaced points of a single fiber not in a web are brought together, it has been observed that the fiber will form a loop and, as the loop is formed, it twists towards a position of minimum internal stress, turning through an angle which tends to approach 180. In carrying out the method because of the great number of fibers in the web and their proximity one to another, each ber loop engages the neighboring fiber loops with the result that all the loops are blocked from turning beyond the plane substantially normal to the machine direction, and are constrained in that position by the interference between the loops. In practice, of course, the actual direction and degree of loop twist depend upon the characteristics of the fibers in the original web 14.

It is important to not, however, that throughout the fabric the heights of the fiber loops vary according to the spacing between the points of attachment of each fiber to the open adhesive pattern in the base web. Referring to FIGS. 5, 8 and 9, it will be seen, for example, that the loop by the fiber portion P between the points of adhesive attachment C, D will have a lower height than the loop formed by the longer fiber portion P between the points A, B. On the other hand, however, successive loops in adjacent diamonds, when viewed in a vertical section taken along the machine direction (FIG. 4), will have the same height since the fiber length P will remain the same between successive sets of points A, B. This results in a dense fabric with the lower loops supporting and filling around the higher loops and the top surface of the fabric being formed by the tops of the higher loops.

The appearance of a fabric so constructed depends not only on the height of the fiber loops but, also, on the type and denier of the fiber used in the base web, and one of the features of the invention is that the depth of the fabric and the evenness of the surface may be varied by adjusting selected ones of the control parameters, as will be explained below. In general, it may be said that for both relatively low and moderate height high-loft materials which have been produced with the method of this invention, the fabric appears to have a uniform thickness with a somewhat uneven surface texture. With very deep highloft fabrics, particularly those made from flexible, low denier fibers, the higher loops tend to lay one over the other, thus providing a very soft, napped, fuzzy, fibrous surface.

To illustrate the effect of varying one of the control parameters, in this case, the angle of the edge of the blade 38 relative to the drum 37 will now be described. Referring to FIG. 6, it will be seen that the blade edge 39 forms an angle a with the line T tangent to the surface of the drum 37. It has been found that the blade edge angle a is one parameter that determines the depth of the fabric produced yand th'e degree of uniformity of construction of the adhesive backing layer.

As a result of trying different blade angles, it has been determined that the preferred blade edge angle a when dealing with adhesive patterns having lines of adhesives spaced approximately 1A apart is between about 17 and about 34. With blades having edge angles within this preferred range, fabrics have been produced which are characterized by having a high degree of uniformity of consolidation of the adhesive backing layer which is substantially void of fissures or gaps and, by having a dense, regular mass of loops that provide a textured, somewhat uneven surface.

With blades having edge angles a less than 17, dificulty has been experienced in obtaining a uniformly consolidated adhesive backing layer. This appears to be the result of insufficient relief between the blade edge and the drum surface for the fabric to flow evenly and smoothly off the drum surface as the result of the action of the blade, which produces varying degrees of consolidation of the adhesive and a non-uniform layer with fissures and gaps and scattered areas where the looping is irregular,

tending to spoil the surface appearance of the fabric. With blades having edge angles substantially above 34, both the problem of non-uniform adhesive consolidation and poor loop formation has been experienced. There is also a tendency as the angle ot of the blade edge is increased substantially above 34 for the fabric to be formed with pronounced ridges, which may be undesirable in the finished product.

In practice, it has been found that one of the major factors effecting the thickness of the fabric is the loop height as determined and limited by the spacing between points of fiber adhesive attachment A-B, C-D, etc. (FIG. 8). To obtain maximum thickness of the fabric with a given adhesive pattern, the blade edge angle a should be such as to produce not only sufficient consolidation of the adhesive layer to provide good ber attachment throughout the fabric but, also, sufficient consolidation to insure the production of a maximum number of full height fiber loops. Thus, as the blade edge angle a increases, the condition is approached Where the web is being skived off the roll rather than being consolidated and gathered. The fabrics produced with higher blade edge angle a have reduced adhesive consolidation and fabric thickness because fewer loops reach their maximum height.

In using a blade 38 having an edge angle a within the preferred range, it has been found that the fabric loft may be regulated by changing the machine direction dimension of the adhesive pattern. Thus, by increasing this dimension, the height of the loops may be increased, thereby increasing the fabric loft. Larger diameter fibers, strands, or yarns may also be used as the elements of the base web to produce heavier, carpet-like finished fabrics. The adhesive and its pattern of application must, however, take into consideration the amount of adhesive required to form the backing layer under the consolidating action of the gathering blade 38, and sufficient adhesive must be present to provide a substantially continuous backing layer of sufficient thickness to obtain strong attachment of the loops in the finished fabric. More specific disclosures of types of adhesive patterns suitable for use in making carpet-like fabrics of larger diameter fibers, strands, or yarns may be found in the aforesaid copending application of Robert I. Stumpf and William I. Mattes, Ser. No. 23,929, and now Pat. No. 3,687,796 and the aforesaid copending application of Herman G. Minshell, Robert J. Stumpf and William I. Mattes, Ser. No. 77,840, both of which are assigned to the assignee of the present invention.

Now turning to a consideration of a different control parameter-viz, the location of the take-away surface 41-the preferred location of the take-away surface is, as shown in the extreme right-hand view in FIG. 7, tight against the blade 38 and even with the outside corner 39' o f the blade. With the surface 41 in this preferred location, the fabric may have a moderately even surface texture and a dense mass of loops forming a deep, high-loft pile.

It has been found that by lowering the take-away surface 41 a distance Y (FIG. 7) from its preferred location, the structure of the fabric will be drastically affected, in that the bulk of the fabric may be increased substantially by lowering the take-away surface 41. The effect of lowering the surface is somewhat similar to the effect from using a blade 38 with an edge angle a substantially above the preferred range nthat pronounced ridges are also produced inv the fabric, thereby increasing its bulk. The amount that the take-away surface is lowered does clearly effect the degree of bulking, and it is apparently the case that as the distance Y increases, the fabric bulk increases.

A further related parameter that affects the gathering function of the blade is the take-away speed of the fabric from the blade edge. With blade 38 having an edge angle a within the preferredrange, and a take-away surface at the preferred location, the take-away speed is desirably regulated to remove the newly formed fabric at the rate at which it is being formed, and it has been found that under these conditions the normal ratio of the surface speed of the heating drum 37 to the take-away speed will be about 12: 1. By increasing the ratio up to, for example, 15:1, by slowing down the fabric take-away speed, more uniform adhesive consolidation has been obtained while the mass of the fiber loops is made somewhat more dense, so that a fabric with a higher Weight has been produced. By increasing the fabric take-away speed, such that the fabric is not allowed to gather at the blade edge 39, the fabric will be drawn or extended while the adhesive layer is still in a plastic condition, thereby opening the adhesive layer, thinning the fabric pile, and reducing the weight of the finished material.

In addition to the diamond pattern, other adhesive patterns which may be used include unevenly spaced lines of application, such as criss-crossed sine waves 80 as shown in FIG. 11. The spacing of such lines of adhesive may furthermore be increased or decreased to change the maximum height of the element loops and, thus, the depth and surface texture of the finished material.

When criss-crossed lines of adhesive are used, the loops of the fabric will have varying heights due to the different spacings of the points of attachments (A-B, C-D-FIG. 8) of the base web elements to the adhesive. To produce a fabric with loops of uniform height, the adhesive is applied to the base web 14 in lines evenly spaced apart and extending across the web. Furthermore, the spacing between the lines of adhesive may be increased or decreased to obtain a higher or a lower pile height, as desired. Referring to FIG. 12, one such adhesive pattern is illustrated in the form of evenly spaced diagonal lines 82. Another such adhesive pattern is illustrated in FIG. 13, in the form of lines 84, each in the shape of a sine wave. A brick-like pattern is another such pattern as shown in FIG. 14. If broken lines of adhesive are utilized to obtain element looping-such, for example, as the bricklike pattern of FIG. 14-the gaps in the lines of adhesive 86 should be staggered so that the web elements longitudinally span the spaces between the adhesive lines and are securely attached to the adhesive.

When the spacing of points of attachment of the fibers to the adhesive varies regularly over the area of the base web as, for example, when an open diamond pattern of adhesive is used, the loops in the finished fabric will vary in height in a regular manner to provide a uniformly varying surface having a textured appearance. When, on the other hand, an open pattern of adhesive is used in which, in the cross direction of the base web 14, the lines of adhesive are parallel, or evenly spaced, it will be seen that the spacing of points of attachment of the elements to the adhesive will be uniform over the total area of the fabric, and the loops in the finished fabric will be of uniform height to provide a more even surface. The appearance of such a surface will, of course, be affected by the characteristics of the elements which form the loops. Thus, Where the elements are yarn or heavy strands of fibers such, for example, as disclosed in the aforesaid copending application of Robert I. Stumpf and William J. Mattes, Ser. No. 23,929, and now Pat. No. 3,687,796, the loops will be clearly visible, while where the elements are small diameter, flexible fibers, the surface will have a fibrous appearance, the fiber looping being less evident.

It has been observed that the transverse adhesive lines, when consolidated by the action of the gathering blade 38, are moved into proximity or abutment with each other and, being in a soft tacky state due to the high temperature of the heating drum 37, tend to bond to each other. However, the bond between lines of adhesive may be broken and the open pattern of adhesive substantially restored by drawing the fabric in the machine direction after the adhesive backing layer has been cooled, all as more clearly described in the aforesaid copending application Ser. No. 820,224, and now Pat. No. 3,687,754.

As is disclosed therein, and referring to FIG. 10, partial consolidation may be attained when the open adhesive pattern is the exemplary diamond pattern. Thus, considering a single diamond S each of the four corners T represents the crossing point of two intersecting lines of adhesive U and V. At every corner T then as the adhesive is scraped along the surface of the drum 40 the crossing adhesive lines U and V are brought closer and closer together. The points closest to the corners T merge first because of the shorter distance of separation. Accordingly, point P5 on line U will merge with point P6 on line V before point P9 will meet point P10. Similarly, on the other side of the corner, the closer set of points (eg-Pq and P8) will merge before points P11 and P12. It can be seen that, if the adhesive were allowed to scrape along the drum surface for a sufficient time period, the open pattern could be consolidated into a substantially continuous adhesive backing, as in the aforesaid copending application, Ser. No. 31,225, and now Pat. No. 3,709,768.

However, in order to form a fabric 44 characterized by its elasticity (a process which as thus broadly defined, is disclosed in more detail in the aforesaid copending application, Ser. No. 820,224, and now Pat. No. 3,687,754), the take-away speed is maintained at a rate so that the adhesive diamonds are not completely consolidated but, rather, are collapsed into fiat hexagonal shapes in which the crossing points of adhesive, as shown in FIG. 10, have been transformed by partial consolidation of the adhesive into lines that form the sides of the highly elongated hexagons. As may be seen in FIG. 3 which is a top plan View of a fabric made in accordance with the present invention with portions broken away, the transverse dimension of the elongated hexagons in the discontinuous adhesive backing is considerably longer than the machine direction.

If desired, the thus-formed elastic fabric could be rolled up and stored or transported elsewhere in this closed position or could be further processed to fabricate a variety of products. Alternatively, since the take-away surface is cooled, by a suitable cooling station as best indicated at 43 (FIG. 1) to render the adhesive non-tacky, only a certain part of the lines of adhesive that are in contact were allowed to establish bonds of any significant strength. Thus, where desired, the closed, compact form of the nonwoven fabric may be stretched apart to break the bonds of minimal strength (ie-the bonds that will break before adhesive rupture or other degradation of the product). The fabric is then allowed to relax to come to an equilibrium state in its drawn or open position.

The drawing may be accomplished by hand and can be achieved by pulling the fabric apart (ie-along the machine direction). Alternatively, shown in FIG. 1, if it is desired to draw the fabric immediately after it has been formed, the fabric exit end of the conveyor 52 may be provided with a roll S5 to form a nip and a pair of rolls 56, 57 also forming a nip. Drawing is accomplished by driving the rollers 56, 57 at a higher speed.

In the application of the adhesive to the base web, it has been observed that by increasing the adhesive viscosity, a sharp, distinct printed pattern will be obtained such that the fibers are securely attached to the adhesive at distinct spaced points and are not embedded in adhesive throughout their length. It is desired to have spaced points of liber adhesive attachment so that the fiber loops will be distinctly and separately formed at the gathering blade in such a manner as to extend outwardly from the adhesive bonding layer. Fiber sizes between 11/2 denier and 15 denier have been successfully utilized in the base web 14 and with a 1A inch diamond pattern of adhesive. With higher denier fibers, or with strands or yarns used in the preparation of the base web, the adhesive pattern is preferably enlarged as described in the aforesaid copending application of Robert I. Stumpf and William J. Mattes, Ser. No. 23,929, now Pat. No. 3,687,796, so as to insure attachment of the fibers or strands to the adhesive at spacings along the length of the threads or yarns which will define the depth of pile or degree of loft in the finished material. With the light-weight webs of rayon the ratio of fiber to adhesive is preferably aproximately 1:1. It has been found that the degree of adhesive fiber attachment in the base web was affected when the fiber-toadhesive ratio with such type fibers was substantially increased above 111, so that the fiber loops did not form properly at the blade 38, nor did the fibers have sufficient attachment to the adhesive layer in the finished fabric. On the other hand, increasing the relative amount of adhesive in the base web had the result of producing a thicker adhesive layer in the finished material and more secure fiber attachment, but the adhesive lines tend to disperse so that the pattern becomes less open, thereby affecting the height of the loops, which is undesirable. The fiberadhesive ratio will be different, however, for base webs of yarns and threads where it appears that less amounts of adhesive, relatively speaking, will provide adequate attachment of the loops to the adhesive backing layer.

While staple length rayon fibers may be used for the preparation of the fabrics, other fibers may also be used in the process in its preferred form, and have resulted in fabrics of excellent properties of hand, drape, and appearance.

For example, acrylic, olefin and polyester fibers have been used, and it is within the contemplation of the invention to use any or all of these fibers by themselves or in blends, as well as natural fibers, acetate, nylon and other synthetic fibers in staple length or in monofilament form, any of which may be used for the preparation of the base web 14.

It has been found that the elements should be sufficiently flexible to allow the loops to form and to twist normal to the machine direction while being formed under the action of the adhesive consolidating and gathering blade 38. Thus, neither stiff strands which do not loop under the action of the gathering blade 38, nor multiple strand yarns in which the lay of the strands opposes the tendency of the loops to twist while being formed under the action of the blade, will satisfactorily serve as elements of the base web 14 when it is desired to produce a high-loft fabric as described.

As shown in FIG. 1, the fabric 40 is carried along the take-away surface 41 by the action of the conveyor S2. Since the adhesive backing is hot and tacky as the fabric fiows onto the take-away surface 41, that surface may be treated with a non-stick or release coating to insure that the fabric may be drawn smoothly along the surface.

To cool the belt of the conveyor 52 and prevent it from becoming overheated from the adhesive backing of the fabric 40, streams of air may be blown against the underside of the belt from suitably placed air nozzles I54. This will also serve to aid the cooling station 43v to cool the fabric 40".

The manufacture of high-loft nonwoven fabric in accordance with the present invention Thus far, the environment of the invention has been described in connection with methods of making high-loft, nonwoven fabrics by preparing a base web comprising an open pattern of adhesive and a plurality of fibers or similar liexible elements extending generally longitudinally in the machine direction thereof and bonded thereto; and, thereafter: (1) reactivating the open pattern of adhesive in which the fibers are embedded; and, (2) consolidating or partially consolidating the adhesive to a backing layer, while (3) simultaneously looping the portions of the fibers spanning the open spaces of the adhesive pattern outwardly from the backing layer formed by the consolidated or partially consolidated adhesive.

In accordance with the present invention, provision is made for forming high-loft, nonwoven fabrics possessing many of the attributes and characteristics of the fabrics hereinabove described, yet which are nonetheless further characterized either by their significantly improved crossdirectional strength characteristics or by their distinctive surface appearance, or both. To this end, provision is made for modifying the structure of the base web formed in the web forming section 12 of the apparatus in a man ner that enables such further desirable characteristics Without unduly interfering with the fiber looping and adhesive consolidating steps that occur during latter stages of the fabric forming process.

In this connection, it is noted that a fully consolidated highloft, nonwoven fabric made as hereinbefore described, typically has a higher tensile strength property in the cross direction than in the machine direction. However, force applied to the fabric in the machine direction tends to deconsolidate or pull the consolidated lines of adhesive apart. In other Words, the fabric will give in the machine direction before it is extensively damaged. Force applied to the fabric in the cross direction of the fabric, however, does not produce similar results. The fabric does not give and in fact ruptures or rips under sufficient stress. Accordingly, the method and apparatus of the present invention is adapted to increase the cross directional strength to minimize the possibility of such rupture by introducing randomly directed fibers, many of which extend in the cross direction of the fabric and thus contribute to the strength of the fabric in the cross direction. In the event the randomly disposed fibers are of different colors than the other fibers, the resulting fabric may have a distinctive, accented surface appearance.

In accordance with this aspect of the invention, and referring to FIGS. 1, l5, 16 and 17 an air forming mechanism 60 for depositing fibers on the open pattern of adhesive is illustrated. As is shown in FIG. 15, the mechanism 60 is adapted to direct fibers to the adhesively printed belt 15 prior to the application of the fiat striated webs of fibers or elements 14a and 14h. Although it is preferred that the mechanism 60 be adapted to direct fibers toward the adhesive pattern prior to applying either of the webs 14a or 14b thereto for the reason that the probability of fibers sticking to the tacky adhesive is greater than it would be in the event one or both of the fiat striated webs 14a and 14b were already present, it should be understood that the mechanism may be positioned between the draw frames 12 and 25, for example, if desired.

In keeping with the present invention, the staple length fibers are directed toward the adhesive by means of the mechanism 60 which is adapted to separate the individual staple length fibers from one or more slivers being fed to the mechanism from supply cans (not shown). The mechanism 60 incorporates the use of multiple air jets to separate the fibers and force them through a forming barrel which is directed toward the adhesive pattern previously applied to the belt 15. Turning to FIGS. 15 and 16, one or more slivers 61 preferably having a weight of about 35-40 grams/yd. and an overall diameter of about 3A; inch are fed into a draw frame indicated generally at 62 which comprises a series of pairs of grooved rolls 63. The rolls of each pair are driven by appropriate gearings (not shown, but well known in the art) at a peripheral rate of speed somewhat faster than the rate of operation of the preceding pair, as was the case for the draw frames 12 and 25 previously described. The pairs of rolls 63 may be adjusted to provide an overall increase in speed and,

ther'efore, an extent of fiber draw on the order of 8:1 through the draw frame 62. The drawn sliver 61 is directed to the inlet end 64 of a forming barrel 65 which may have an inside diameter of approximately one inch. Although the length of the barrel 65 is not critical, a barrel length of approximately 8 to l0 inches functioned satisfactorily.

To provide the air stream that supplies the force for separating the fibers from the sliver 61, a pair of oppositely disposed air nozzles 67 are provided. Each of the air nozzles have internal passages 68 communicating with air passage 69 which in turn communicates with three orifices 70. The orifices 70 have an inside diameter of of approximately M34 of an inch and are aligned at an angle a that is within the range of about 35 55 and preferably about 45 relative to the axis of the barrel and sliver 61. The forming barrel 65 as well as the air nozzles 67 are structurally supported by a collar 71 which is suitably attached to a frame or the like (not shown). The inlet side 64 of the forming barrel 65 is preferably outwardly fiared to enable the air passing from the orifices 70 to smoothly enter the forming barrel and insure that substantially all of the sperated fibers from the sliver 61 enter the barrel.

Air from a source (not shown) is supplied through conduits or tubing 73 which are connected to the nozzles 67 in communication with the internal passage 68. With the orifices 70 having an inside diameter of %4 inch, a generally constant pressure with the range of about p.s.i. to about p.s.i. provides airstreams eminating from the orifices 70 that have sufficient velocity to separate the individual fibers from the sliver 61 as well as force the separated fibers through the barrel and onto the adhesively printed belt 15. It has been found that the use of three inlined orifices 70 in each of the air nozzles 67 were required to separate and carry the fibers from the sliver 61 to the adhesive pattern, as single orifices produced a spiraling within the barrel which twisted separate fibers into a rope-like structure rather than independently carrying them to the adhesive. In this connection, the oppositely directed air streams are directed to meet at the axis of the barrel and the fibers of the sliver are subjected to a pinching force that is sufficient to separate the fibers from the sliver. The distance between the nip of the last downstream draw frame rolls should be spaced slightly less than the fibers length so that the fibers will be supported by the nip until they are impinged by the air jets and separated to enter the barrel. Thus, the fibers may be within the range of approximately 1/2 inch to 3 inches.

The separated fibers are directed through the forming barrel 65 and, due to the turbulence created therein, the oppositely directed streams of air tend to oscillate or agitate the fibers which is conducive to spreading the fibers so that they are applied throughout a much larger distribution pattern when they contact the adhesive pattern and are randomly applied in terms of directions so that they extend both in the machine and cross directions.

In this connection, it has been found that the distance d between the outlet end of the barrel and the position where the fibers are directed on the belt should be determined so that substantially all of the fibers passing through the barrel impinge upon the adhesive pattern rather than pass beyond the outside edges of the belt. Additionally, the velocity of the air separating the fibers from the sliver and forcing the fibers through the barrel is a factor in determining the distance d since the fibers lshould have sufficient momentum to reach the adhesive pattern, but should preferably not be caused to roll or move once they have contacted the adhesive. A distance d of approximately 18 inches has been found to produce good fiber distribution on a belt having a width of 12 inches with an air supply pressure of about 5 p.s.i.

In keeping with the invention, it is preferred that the forming barrel 65 be angularly disposed relative to the plane of the belt at and angle 0 which is within the range of about 40-50 and preferably about 45 as shown in FIG. 15. A substantially lesser angle 0 may cause the fibers to skip or deflect off of the adhesive pattern, while angles substantially greater than 45 have resulted in less desirable distribution, due in part to the air bouncing back into the air stream carrying the fibers. An angle 0 of about 45 permits the air to carry the fibers to the adhesive pattern on the belt 15 while permitting the air to exit out of the way as the belt moves downstream.

In accordance with another aspect of the present invention, the fibers of the sliver 61 may be of a different color than the fibers of the fiat striated Webs 14a and 14b that are applied in overlapping relation by the draw frames 12 and 25. By so doing the resultant high-loft nonwoven fabric formed after consolidation may have a splotchy marbelized appearance depending upon the density of fibers that are applied by the air forming mechanism 60. The density of the air formed fibers are, of course, a function of the rate of feed of the slivers 61 and, since the slivers are subjected to multiple drawing from the action of the rolls 63, the fibers wil-l be generally independently separated from the drawn sliver and deposited generally uniformly on the adhesive pattern. Such uniform deposition throughout the Isurface area of the belt having the adhesive pattern thereon results in fibers extending in the cross direction throughout and increases the cross-directional strength of the resulting high-loft, nonwoven fabric without unduly impairing the looped formation during consolidation. In the event a sliver 61a is introduced into the draw frame toward the downstream end thereof or if the `speed of the pairs of rollers are not as great so that the sliver drawing is reduced, the sliver exiting from the downstream end of the draw frame 62 necessarily will be more dense. The action of the air impinging upon the denser sliver Will separate clumps of fibers rather than separate individual fibers and will cause clumps of fibers to be applied to the adhesive pattern. Such action thereby produces clumps or splotches of the fibers which, after consolidation by the consolidating and gathering section 30, produces a splotchy, marbelized appearance without substantially detracting from the loop formation.

It should be understood that multiple air forming mechanisms may be utilized to air form fibers across a belt that has a greater width. Additional air forming mechanisms 60 may be successively positioned downstream of one another to deposit a combination of generally uniform fibers thereon as well as splotches or clumps of fibers to vary the cross-directional strength of the resulting high-loft, nonwoven fabric as well as its appearance. It is also contemplated that an elongated slot or duct extending continually across the width of the belt 15 may be used rather than one or more forming barrels 65.

Thus, a new and useful method in the preparation of a high-loft, nonwoven material has been described which can be varied to produce an unusual marbelized and attractive visual appearance as well as increase the crossdirectional strength of the resulting fabric as desired.

What is claimed is:

1. A method for producing a high-loft, nonwoven fabric, comprising:

advancing a surface having an open pattern of tacky adhesive thereon in a machine direction;

bonding a plurality of flexible elements in the adhe sive, the elements extending in the machine and cross directions thereof;

preparing a web including other fiexible elements extending substantially in the machine direction; bonding the other elements of the web in the open pattern of adhesive;

reactivating the adhesive to a tacky state;

at least partially consolidating the open pattern of tacky adhesive at a consolidation station (i) to form a backing layer (ii) while looping the elements extending in the machine direction and located in the open spaces of the adhesive pattern outwardly from the backing layer;

the elements extending in the cross direction increasing the cross directional strength of the fabric.

2. A method as defined in claim 1 wherein the plurality of fiexible elements are randomly bonded in the adhesive on said surface to produce a discontinuous irregular density of fibers extending in the machine and cross directions.

3. A method as defined in claim 2 wherein the color of the plurality of tiexible elements differs from the color of the other exible elements of said web such that the resulting high-loft nonwoven fabric has a splotchy, marbelized appearance.

4. A method as defined in claim 1 wherein the plurality of exible elements and the web of other exible elements are staple length fibers.

5. A method as dened in claim 1 wherein the plurality of exible elements and the web of other flexible elements are selected from a group consisting of `synthetic yarns, natural yarns, synthetic threads, natural threads or blends thereof.

6. A method as defined in claim 1 wherein the plurality of flexible elements are bonded in the adhesive substantially uniformly throughout the area of the surface having the open pattern of adhesive.

7. A method as dened in claim 1 wherein the open pattern of a tacky adhesive is substantially fully consolidated to form a substantially continuous `backing layer. 8. A method as delined in claim 1 wherein the open pattern of adhesive comprises a series of interconnected diamonds.

9. A method as defined in claim 1 wherein reactivation of the adhesive to a tacky state is achieved by carrying the web onto a heated surface, and

at least partial consolidation of the open pattern is achieved by impinging the elements and the tacky adhesive against the edge of a relatively moving gathering blade.

10. A method as dened in claim 1 wherein the open pattern of tacky adhesive is partially consolidated to form a partially consolidated backing layer and the adhesive and outwardly looped elements are conveyed away from the consolidating station at a rate suicient to minimize bonding of the adhesive backing, while allowing the outwardly looped elements to cool to thereby produce an elastic high-loft nonwoven material.

11. A method as defined in claim wherein the adhesive backing and outwardly looped elements being conveyed away from the consolidating station are conditioned to provide heat-setting conditions for the outwardly looped elements while rendering the adhesive backing non- 18 tacky to minimize bonding of the adjacent portions of the partially consolidated backing layer.

12. A method as defined in claim 1 wherein said plurality of flexible elements are bonded in said adhesive pattern by directing a turbulent gaseous stream having elements therein toward said surface having said pattern of adhesive.

13. A method as defined in claim 12 wherein a pair of oppositely directed air jets are positioned on opposite sides of a forming barrel adjacent the free end of a sliver of elements, each of said air jets being at an angle of about 35-55 relative to the axis of the sliver and having a predetermined velocity suicient to separate said elements from said sliver and carry them through said barrel to said surface.

1 4. A method as defined in claim 13 wherein varying the rate of feed of said slivers effects the distribution pattern of said elements contacting said adhesive pattern, whereby increasing the feed rate is effective to cause clumps of elements to contact said adhesive and thereby produce splotches in the fabric.

15. A method as defined in claim 12 wherein said gaseous stream is at an angle of about 40-50 relative to the Plane of said surface.

References Cited UNITED STATES PATENTS 2,550,686 5/1951 Goldman 156-471 2,639,250 5/1953 Reinhardt 161-65 3,142,611 7/1964 Mills 161-66 3,214,323 y10/1965 Russell et al. 161-148 3,220,056 11/1965 Walton 18-19 3,236,718 2/1966 Cohn et al 161-128 GEORGE F. LESMES, Primary Examiner J. J. BELL, Assistant Examiner U.S. Cl. X.R. 1 

